fix #6066 Support optional filename in HttpPostRequestEncoder

Motivation:

According to https://www.ietf.org/rfc/rfc2388.txt 4.4, filename after "content-disposition" is optional and arbitrary (does not need to match a real filename).

Modifications:

This change supports an extra addBodyFileUpload overload to precise the filename (default to File.getName). If empty or null this argument should be ignored during encoding.

Result:
- A backward-compatible addBodyFileUpload(String, File, String, boolean) to use file.getName() as filename.
- A new addBodyFileUpload(String, String, File, String, boolean) overload to precise filename
- Couple of tests for the empty use case

codec-http/src/main/java/io/netty/handler/codec/http/multipart/HttpPostRequestEncoder.java

@@ -34,6 +34,7 @@ import io.netty.handler.codec.http.HttpUtil;
 import io.netty.handler.codec.http.HttpVersion;
 import io.netty.handler.codec.http.LastHttpContent;
 import io.netty.handler.stream.ChunkedInput;
+import io.netty.util.internal.StringUtil;
 import io.netty.util.internal.ThreadLocalRandom;
 
 import java.io.File;
@@ -362,12 +363,39 @@ public class HttpPostRequestEncoder implements ChunkedInput<HttpContent> {
      */
     public void addBodyFileUpload(String name, File file, String contentType, boolean isText)
             throws ErrorDataEncoderException {
+       addBodyFileUpload(name, file.getName(), file, contentType, isText);
+    }
+
+    /**
+     * Add a file as a FileUpload
+     *
+     * @param name
+     *            the name of the parameter
+     * @param file
+     *            the file to be uploaded (if not Multipart mode, only the filename will be included)
+     * @param filename
+     *            the filename to use for this File part, empty String will be ignored by
+     *            the encoder
+     * @param contentType
+     *            the associated contentType for the File
+     * @param isText
+     *            True if this file should be transmitted in Text format (else binary)
+     * @throws NullPointerException
+     *             for name and file
+     * @throws ErrorDataEncoderException
+     *             if the encoding is in error or if the finalize were already done
+     */
+    public void addBodyFileUpload(String name, String filename, File file, String contentType, boolean isText)
+            throws ErrorDataEncoderException {
         if (name == null) {
             throw new NullPointerException("name");
         }
         if (file == null) {
             throw new NullPointerException("file");
         }
+        if (filename == null) {
+            filename = StringUtil.EMPTY_STRING;
+        }
         String scontentType = contentType;
         String contentTransferEncoding = null;
         if (contentType == null) {
@@ -380,7 +408,7 @@ public class HttpPostRequestEncoder implements ChunkedInput<HttpContent> {
         if (!isText) {
             contentTransferEncoding = HttpPostBodyUtil.TransferEncodingMechanism.BINARY.value();
         }
-        FileUpload fileUpload = factory.createFileUpload(request, name, file.getName(), scontentType,
+        FileUpload fileUpload = factory.createFileUpload(request, name, filename, scontentType,
                 contentTransferEncoding, null, file.length());
         try {
             fileUpload.setContent(file);
@@ -615,12 +643,17 @@ public class HttpPostRequestEncoder implements ChunkedInput<HttpContent> {
 
                         .append(HttpHeaderNames.CONTENT_DISPOSITION)
                         .append(": ")
-                        .append(HttpHeaderValues.ATTACHMENT)
+                        .append(HttpHeaderValues.ATTACHMENT);
-                        .append("; ")
+
+                    if (!fileUpload.getFilename().isEmpty()) {
+                        replacement.append("; ")
                                    .append(HttpHeaderValues.FILENAME)
                                    .append("=\"")
                                    .append(fileUpload.getFilename())
-                        .append("\"\r\n");
+                                   .append('"');
+                    }
+
+                    replacement.append("\r\n");
 
                     pastAttribute.setValue(replacement.toString(), 1);
                     pastAttribute.setValue("", 2);
@@ -648,17 +681,32 @@ public class HttpPostRequestEncoder implements ChunkedInput<HttpContent> {
                 // add mixedmultipart delimiter, mixedmultipart body header and
                 // Data to multipart list
                 internal.addValue("--" + multipartMixedBoundary + "\r\n");
+
+                if (fileUpload.getFilename().isEmpty()) {
+                    // Content-Disposition: attachment
+                    internal.addValue(HttpHeaderNames.CONTENT_DISPOSITION + ": "
+                            + HttpHeaderValues.ATTACHMENT + "\r\n");
+                } else {
                     // Content-Disposition: attachment; filename="file1.txt"
-                internal.addValue(HttpHeaderNames.CONTENT_DISPOSITION + ": " + HttpHeaderValues.ATTACHMENT + "; "
+                    internal.addValue(HttpHeaderNames.CONTENT_DISPOSITION + ": "
+                            + HttpHeaderValues.ATTACHMENT + "; "
                             + HttpHeaderValues.FILENAME + "=\"" + fileUpload.getFilename() + "\"\r\n");
+                }
             } else {
                 internal.addValue("--" + multipartDataBoundary + "\r\n");
+
+                if (fileUpload.getFilename().isEmpty()) {
+                    // Content-Disposition: form-data; name="files";
+                    internal.addValue(HttpHeaderNames.CONTENT_DISPOSITION + ": " + HttpHeaderValues.FORM_DATA + "; "
+                            + HttpHeaderValues.NAME + "=\"" + fileUpload.getName() + "\"\r\n");
+                } else {
                     // Content-Disposition: form-data; name="files";
                     // filename="file1.txt"
                     internal.addValue(HttpHeaderNames.CONTENT_DISPOSITION + ": " + HttpHeaderValues.FORM_DATA + "; "
                             + HttpHeaderValues.NAME + "=\"" + fileUpload.getName() + "\"; "
                             + HttpHeaderValues.FILENAME + "=\"" + fileUpload.getFilename() + "\"\r\n");
                 }
+            }
             // Add Content-Length: xxx
             internal.addValue(HttpHeaderNames.CONTENT_LENGTH + ": " +
                     fileUpload.length() + "\r\n");

codec-http/src/test/java/io/netty/handler/codec/http/multipart/HttpPostRequestEncoderTest.java

@@ -74,6 +74,39 @@ public class HttpPostRequestEncoderTest {
         assertEquals(expected, content);
     }
 
+    @Test
+    public void testSingleFileUploadNoName() throws Exception {
+        DefaultFullHttpRequest request = new DefaultFullHttpRequest(HttpVersion.HTTP_1_1,
+                HttpMethod.POST, "http://localhost");
+
+        HttpPostRequestEncoder encoder = new HttpPostRequestEncoder(request, true);
+        File file1 = new File(getClass().getResource("/file-01.txt").toURI());
+        encoder.addBodyAttribute("foo", "bar");
+        encoder.addBodyFileUpload("quux", "", file1, "text/plain", false);
+
+        String multipartDataBoundary = encoder.multipartDataBoundary;
+        String content = getRequestBody(encoder);
+
+        String expected = "--" + multipartDataBoundary + "\r\n" +
+                CONTENT_DISPOSITION + ": form-data; name=\"foo\"" + "\r\n" +
+                CONTENT_LENGTH + ": 3" + "\r\n" +
+                CONTENT_TYPE + ": text/plain; charset=UTF-8" + "\r\n" +
+                "\r\n" +
+                "bar" +
+                "\r\n" +
+                "--" + multipartDataBoundary + "\r\n" +
+                CONTENT_DISPOSITION + ": form-data; name=\"quux\"\r\n" +
+                CONTENT_LENGTH + ": " + file1.length() + "\r\n" +
+                CONTENT_TYPE + ": text/plain" + "\r\n" +
+                CONTENT_TRANSFER_ENCODING + ": binary" + "\r\n" +
+                "\r\n" +
+                "File 01" + StringUtil.NEWLINE +
+                "\r\n" +
+                "--" + multipartDataBoundary + "--" + "\r\n";
+
+        assertEquals(expected, content);
+    }
+
     @Test
     public void testMultiFileUploadInMixedMode() throws Exception {
         DefaultFullHttpRequest request = new DefaultFullHttpRequest(HttpVersion.HTTP_1_1,
@@ -124,6 +157,56 @@ public class HttpPostRequestEncoderTest {
         assertEquals(expected, content);
     }
 
+    @Test
+    public void testMultiFileUploadInMixedModeNoName() throws Exception {
+        DefaultFullHttpRequest request = new DefaultFullHttpRequest(HttpVersion.HTTP_1_1,
+                HttpMethod.POST, "http://localhost");
+
+        HttpPostRequestEncoder encoder = new HttpPostRequestEncoder(request, true);
+        File file1 = new File(getClass().getResource("/file-01.txt").toURI());
+        File file2 = new File(getClass().getResource("/file-02.txt").toURI());
+        encoder.addBodyAttribute("foo", "bar");
+        encoder.addBodyFileUpload("quux", "", file1, "text/plain", false);
+        encoder.addBodyFileUpload("quux", "", file2, "text/plain", false);
+
+        // We have to query the value of these two fields before finalizing
+        // the request, which unsets one of them.
+        String multipartDataBoundary = encoder.multipartDataBoundary;
+        String multipartMixedBoundary = encoder.multipartMixedBoundary;
+        String content = getRequestBody(encoder);
+
+        String expected = "--" + multipartDataBoundary + "\r\n" +
+                CONTENT_DISPOSITION + ": form-data; name=\"foo\"" + "\r\n" +
+                CONTENT_LENGTH + ": 3" + "\r\n" +
+                CONTENT_TYPE + ": text/plain; charset=UTF-8" + "\r\n" +
+                "\r\n" +
+                "bar" + "\r\n" +
+                "--" + multipartDataBoundary + "\r\n" +
+                CONTENT_DISPOSITION + ": form-data; name=\"quux\"" + "\r\n" +
+                CONTENT_TYPE + ": multipart/mixed; boundary=" + multipartMixedBoundary + "\r\n" +
+                "\r\n" +
+                "--" + multipartMixedBoundary + "\r\n" +
+                CONTENT_DISPOSITION + ": attachment\r\n" +
+                CONTENT_LENGTH + ": " + file1.length() + "\r\n" +
+                CONTENT_TYPE + ": text/plain" + "\r\n" +
+                CONTENT_TRANSFER_ENCODING + ": binary" + "\r\n" +
+                "\r\n" +
+                "File 01" + StringUtil.NEWLINE +
+                "\r\n" +
+                "--" + multipartMixedBoundary + "\r\n" +
+                CONTENT_DISPOSITION + ": attachment\r\n" +
+                CONTENT_LENGTH + ": " + file2.length() + "\r\n" +
+                CONTENT_TYPE + ": text/plain" + "\r\n" +
+                CONTENT_TRANSFER_ENCODING + ": binary" + "\r\n" +
+                "\r\n" +
+                "File 02" + StringUtil.NEWLINE +
+                "\r\n" +
+                "--" + multipartMixedBoundary + "--" + "\r\n" +
+                "--" + multipartDataBoundary + "--" + "\r\n";
+
+        assertEquals(expected, content);
+    }
+
     @Test
     public void testSingleFileUploadInHtml5Mode() throws Exception {
         DefaultFullHttpRequest request = new DefaultFullHttpRequest(HttpVersion.HTTP_1_1,